PLEASE DO NOT DIRECTLY MODIFY THIS PAGE, AS IT IS JUST HIXIE'S NOTES. IF YOU WANT TO CONTRIBUTE TO THIS PAGE, EITHER ADD EXAMPLES OF REAL-WORLD USE CASES TO THE TWO PAGES ABOVE, OR E-MAIL HIXIE OR THE LIST.

for off-video display (lyrics), disabled by default in this version, not shown by UA

for metadata (slide timings, annotation data for app-rendered annotations), enabled by default, not shown by UA

Tracks that are for visual display or audio playback have additionally a user-facing label and a language.

Tracks that are for visual display have an additional boolean indicating if they include sound effects and speaker identification (intended for the deaf, hard of hearing, or people with sound muted) or not (i.e. translations intended for people with audio enabled but who cannot understand the language, or karaoke lyrics).

Each timed track associated with a media resource, like the media resource itself, can have multiple sources.

Each source for a timed track has:

URL

type (if there are multiple sources)

media

The media resource can also imply certain timed tracks based on data in the media resource.

The script can also add "virtual" timed tracks dynamically.

Markup

<track src="" enabled="true" kind="" label="" lang=""></track>

<track enabled="true" kind="" label="" lang="">

<source src="" type="" media="">
...

</track>

enabled="" is true or false.

Values for kind="":

subtitles (includes karaoke) - default

captions

description (text audio descriptions)

chapters

lyrics

metadata

Questions:

Should we use lang="", hreflang="", srclang=""?

Is there a better solution to enabled=false for disabling tracks by default? Do we ever need to disable a track that might be enabled by default?

Visual titles

File format

...

Processing model

...

CSS extensions for styling captions

...

DOM API

...

Other minor things

We need to make sure that media playback is paused until all enabled timed tracks are locally available.

Open issues

How do we handle sign-language tracks?

Do we handle multiple alternate audio tracks from this or is that restricted to in-band data? (in the media resource)

Do we need to handle live transcription and streaming titles in external files? If so, how?